Cast-off mechanism for sewing machines



May 14, 1929. LEVEQUE 1,713,186

CAST-OFF MECHANISM FOR SEWING MACHINES 7 Original Filed Feb. 2,.1924

745172336 men/1227' Kw! u Patented May 14, 1929.

UNITED STATES PATENT OFF-ICE.

BERNARD T. LEVEQUE, 0F WENHAM, MASSACHUSETTS, ASSIGNOR TO UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW JERSEYfA CORPORATION 01' NEW JERSEY.

CAST-OFF MECHANISM FOR SEWING MACHINES.

Original application filed February 2, 1924, Serial No. 690,265. Divided and this application filed February 15, 1927.

The present invention relates to cast olfs for hook needle sewing machines and is herein disclosed as embodied in a chain stitch shoe sewing machine of the so-called McKay type, the stich forming devices of which comprise astraight hookneedleand the work support of which consists of a rotatable horn arranged to extend within the shoe and provided at its tip with a needle threadlng device or whirl for laying the thread in the hook of the needle- I The primary object of the invention is to produce a new and improved cast-off mechanism particularly adapted for use in machines of this description which is simple and durable in construction and will oper ate accurately and without excessive wear at high speeds.

A further object of the invention is to provide a new and improved cast-off mecha nism which will operate to leave the needle hook uncovered when the needle is stopped at the limit of its loop drawing stroke.

WVith these objects in view the several features of the invention consist in the devices,

; combinations and arrangement of parts hereinafter described and claimed, certain of;

which, while particularly adapted for use in sole sewing machines of the McKay type, are also capable of use machines.

The several features of the invention and the advantages obtained thereby will be readily understood by those skilled in the art from the following description taken' in connection with the accompanying drawings which illustrate the invention "as embodied in a chainstitch McKay sewing machine.

The drawing is a view in front elevation of the head-of a chain stitch McKay sewing ma chine embodying one forinof the present invention only so muchof the machine being illustrated as is necessary to show the connection of thepresent invention therewith.

For a full description of the machine, reference may be had to the inventors pending application Serial'No. 690,265, of which the present application is a division.

The cast-off mechanism embodying specifically the subject matter of the present invention comprises a supporting collar to which the cast-off is secured loosely sleevedon the needle bar toslide between set stops on in other types ofsewing Serial N0. 168,253.

the'bar, andtwo oppositely arranged spring pressed levers provided with cam surfaces adapted to engage a roll on the collar and so control the movement of the cast-off with relation to the needle.

The yielding cam levers take the place of the friction devices usually employed to secure a delayed motion of the cast-0d with relation to the needle and also act to impart an additional movement to the cast-off in the direction of movement of the needle bar at the end of the stroke in each direction to uncover the needle barb at the top of the stroke and toproject'the cast-off yieldingly into contact with the work on the down stroke of the needle.

Referring specifically to the drawings-the needle is indicated vat 4, the .presser foot at 6,

the feed point at 8, a hornof usual construcneedle bar to be disconnected from the sew- I ing shaft at the top of its stroke at the end .of the sewing operation. To reciprocate the needle bar a'block 20 is secured to thebar and is connected by a link 22 to a lever 24 pivoted'at 26 to a lever 28 ,'which lever is 'secured at its right-hand end to a pivot shaft 30,. 'Therig'ht-hand end of the lever 24, as viewed from the front end of the machine,is

provided with a curved slot 32, which is en- .gaged a block 34 pivotally mounted on the A upper end of an arm 36, which is automatically adjusted to vary the throw ofthe lever 24, and the needle bar 14;, in accordance with the thicknessof the work. The lever 28 is actuated to drive the needle bar by means of a lever 38 mounted parallel to the lever 28 and secured at its'right-hand end to thesleeve 40 surrounding the pivot shaft 30 of the lever -28. A cam slot 44 is formed in the lever 38,

which cam slot is engaged bythe crank pin 16 so that during the rotation of the cam shaft the lever 38 is continuously oscillated. To cause the lever-28 to. oscillate with the lever 38 a latch 46jis' mounted span the left= hand end ofthe lever 28 and arranged to engage a pin 18 on the lever 38. During the sewing operation the latch is held in engagement with the pin by means of a spring surrounding the pivot or the latch.

As more fully pointed out in the inventors pending application above referred to, the machine is provided with connections from the starting and stopping treadle for actuating the latch -16 to disconnect the needle bar :trom the sewing cam wait as the needle bar reaches the top of its stroke. These connections include a vertically arranged lever arm 50 provided at its upper end with a cam groove 52 which is adapted to receive a roll 54- mounted on the needle actuating lever 28. During the operation of the machine the lever 50 is swung yieldingly to the right so that the roll rides on the left side of the cam groove.

However, when the treadle is lifted to stop the machine, the lever 50 will be swung yieldingly to the left so that the roll 54*. riding up the right side ot' the cam groove will enter the notch 58 locking the needle lever in raised position. At the sameinstant, the latch 46 will be disconnected from the lever 38 which will continue to oscillate with each rotation of the sewing cam shaft. i

The mechanism for actuating the cast-otl herein disclosed, is simple and durable in construction, and is adapted to operate accurately and without excessive wear at the v unusually high speed at which the chain stitch McKay sewing machine embodying the present invention is intended-to operate. Furthermore, in order to permit the operator more readily to disengage the thread from the barb of the needle after-the machine has come to rest without cutting the thread, the

cast-oft mechanism is actuated in such a manner as to leave the needle hook uncovered at the limit of the loop drawing stroke so that when the sewing mechanism is stopped, the needle hook will be uncovered. This is of advantage, for instance, when an imperfection occurs in the seam for the operator can then, merely by pulling the shoe oil and away from the horn, rip out the stitches which have been sewed as far back along the seam as he desires.

The cast-oil 12 is mounted to slide in a groove in the needle bar and is secured at its upper end by means of a bolt 62, through which the cast-oft passes, to a collar 60 loose- 1y sleeved to the needle bar 14;. A slot 64 is cut in'the needle bar to receive the head of the bolt which is provided at its outer end with a nut 66 to actuate the bolt so as to clamp the cast-cit firmly against the inner face of the collar 60. This collar is mounted to slide on the needle bar between the block 20 and a collar 68 secured to the needle bar. Upon the collar 60 is mounted a roll 70 which, as the needle bar is moved up and down, passes between the upper ends of levers 72 and 74: pivotally mounted on the machine frame and connected at the lower ends by intermeshing teeth, whereby their upper ends are caused to move toward and from each other in unison. The upper ends of the levers are forced to gether by a spring 76 connecting the levers.

needle bar reaches the limit 01 its down stroke,

the roll will have moved past the point of contact ot the levers 72 and is given an additional impulse downward into yielding engagement with the work by the contracting action oil the levers under the influence of the spring 76. During the retracting or loop drawlng stroke of the needle, the cast-oil remains in contact with the work until the needle hook is covered, when the collar 60 will be engaged by the collar 68 secured to the needle bar moving the cast-off upwardly with the needle and causing the roll 70 again to pass between the levers 12 which act as the needle reaches the limit of its loop drawing stroke to give the cast-oil. an additional impulse upwardly to uncoverthe needle hook. 1

The nature and and scope of the invention havingbeen indicated and a form of the invention having been specifically described, what is claimed is: y

1. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a cast-oil" movable with the needle and having a limited independent movement, a pin connected tothe cast-oft, and a yielding member engaged by the pin during the needle movement provided with a ,cam

surface for moving the castofi' to uncover the needle book as the needle reaches the limitof its loop drawing stroke.

2. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a cast-oif movable with the needle and having a limited independent movement, a pin connected to the cast-off, and a yielding member engaged by the pin during the needle movement provided with cam surfaces for moving the cast-oft with relation to the needle in the direction of needle movement during the movement of the needle in each direction.

3. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a cast-off movable with the needle and having a limited independent movement, a pin connected to the CitSt-Ofi, and yielding members, between which the pin passes during the needle movement, connected to'move in unison towards and from each other and provided with cam surfaces for moving the cast-off to uncover the needle.

hook as the needle reaches the limit of its loop drawing stroke.

4. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a needle bar provided with a groove, a sleeve loosely mounted to move on the needle bar with and independently of the needle, and a: cast-off mounted to slide in said groove secured to the sleeve.

5. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a cast-01f mounted to move with and independently of the needle, and means for imparting tothe cast-oil an additional impulse in the direction of the needle stroke to uncover the needle barb at the end of the loop drawing stroke and to bring the cast-off yieldingly into contact with the work on the down stroke of the needle.

6. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a cast-off mounted to move with and independently of the needle,

means for causing the cast-01f to move with the needle and means for imparting to the cast-off an additional impulse on the down stroke of the needle to bring the cast-ofi yieldingly into contact with the work.

A sewing machine having, in combination, stitch forming devices including a straight hook needle, a needle bar, a sleeve loosely mounted to move on the needle bar, a cast-off, a bolt through which the cast-ofl' passes extending outwardly through the sleeve, and a nut for tightening'the bolt'to clamp the cast-off to the sleeve.

8. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a cast-off movable with the needle and having a limited independent movement, a pin connected to the castofi', and a yielding member engaged by the pin during the needle movement provided with a cam surface for moving the cast-oil yieldingly towards the work as the needle reaches the limit ofits down stroke.

9. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a needle bar, a cast-off adapted to slide in a groove in the-needle bar, a sleeve loosely mounted to move 011 the needle bar, and means for clamping the cast off to the inner surface of the sleeve.

10. A sewing machine having, in combination, stitch forming devices including a straight hook needle, a needle bar, acast-off adapted to slide in a groove in the needle bar, a sleeve loosely mounted to slide on the needle bar, a bolt through which the cast-off passes extending outwardly through the sleeve, and

a nut for tightening the bolt to cast-off to the inside of the sleeve.

In testimony whereof I have signed my name to this application.

BERNARD T. LEVEQUE.

clamp the 

